A few weeks ago, when she arrived for the New York Film Festival premiere of “Changeling,” the new Clint Eastwood drama in which she stars, she brought along her partner of three years, Brad Pitt, and their sons, Maddox, 7, and Pax, 4, daughters Zahara, 3, and Shiloh, 2, and 3-month-old twins Knox and Vivienne. The eight of them had flown in from Germany, where the family has settled while Mr. Pitt shoots Quentin Tarantino’s World War II adventure “Inglorious Bastards.”

“We’re all a little jet-lagged,” she said, not looking jet-lagged in the least as she settled in for a brief stay at the Waldorf-Astoria before moving the clan on to New Orleans. Carrying a lot of baggage is something Ms. Jolie seems to greet with serenity — as a mother. As an actress, however, she knows it poses a potential problem.

At 33 she occupies a rare place within Hollywood’s uppermost tier of female stars. Wherever she goes, whatever she does, she cannot escape her several identities. The serious actress who won an Oscar for 1999’s “Girl, Interrupted” and much acclaim for playing Mariane Pearl, widow of the murdered journalist Daniel Pearl, in last year’s “Mighty Heart” is also the dominatrix-ish action dynamo who can open slam-bang guy movies, like this summer’s “Wanted.” There’s also the humanitarian activist who has served as a United Nations good-will ambassador and is now a member of the Council on Foreign Relations. And there’s her role as half of Brangelina, an unincorporated business that remains the celebrity magazine industry’s best bet for surviving the economic crisis.

Ms. Jolie, who is disarmingly easygoing and more delicately beautiful and finely featured than red-carpet photographs suggest, said she mostly manages to ignore her alternate plane of existence as a tabloid sensation. She lives “in a bit of a bubble when it comes to people’s perceptions of me, which I’m sure is a very good thing,” she said, laughing, “because I’m sure it’s not always very nice.”

If Ms. Jolie finds the attention irritating, she’s too smart to complain about it. But she admits that the wealth of available information about her could create a self-defeating conundrum. Her ever-growing fame could endanger her ability to do the very job that made her famous in the first place — to make audiences believe she’s somebody else. In short, to vanish.

“Can I do that?” she asked. “I certainly hope so. I wouldn’t put myself forward to do a film like ‘Changeling’ if I thought I couldn’t pull people into a story because of all the other ways people see me.”

In “Changeling” Ms. Jolie plays Christine Collins, a switchboard supervisor and single mother in 1928 Los Angeles whose 9-year-old son is kidnapped. (The story has its roots in a series of gruesome killings known as the Wineville Chicken Coop Murders.) Five months after the child’s disappearance, the Los Angeles Police Department hands her a boy it insists is her son, and department officials attempt to destroy her life when she says they’re wrong. The role, in which Ms. Jolie must embody the agony of not knowing if her only child has been murdered, puts her, in some ways, back in the wrenching territory of her last drama, “A Mighty Heart.”

When Ms. Jolie first read the “Changeling” script, “I said, this is absolutely great, and I never want to do it,” she recalled. “I don’t want to put my consciousness on children being kidnapped. But I couldn’t forget about her. I found myself telling Brad and friends of mine the story.”

“Changeling” arrived at an especially painful moment for Ms. Jolie. In January 2007 her mother, Marcheline Bertrand, died of ovarian cancer at 56. “My mom, she was a very, very soft woman,” she said. “It was hard for her to yell, or even curse. But when it came to fighting for her kids, she found a strength she didn’t always know she had. And there’s a part of Christine that I connected to her. I kept pictures of my mom in the little purses” that her character carries in the movie.

Grief hit Ms. Jolie hard — and led, oddly, not to “Changeling” but to “Wanted,” a blood-splashed, R-rated comic-book adaptation in which she gives what she wryly called “my Clint Eastwood performance” as a ruthless, almost superhuman gunslinger who utters barely two dozen lines.

“I knew instinctively that I needed something before ‘Changeling,’ ” she said. “I was depleted. I was in a state of just wanting to pull the covers over my head and cry about my mom. It was just too much. For me, there have been times when an action movie, even a ‘Tomb Raider,’ has helped me get out of myself and be physical again. It’s like therapy.”

Ms. Jolie, who says she doesn’t particularly like to watch her own work, hasn’t seen “Wanted.” The film has grossed more than $300 million worldwide. “I’m glad it worked out,” she said with a smile.

She has, however, seen “Changeling.” “Clint asked me to,” she said. “What are you going to do, say no to Clint?” Except for a brief hello years ago backstage at CNN’s “Larry King Live,” Ms. Jolie said she had never met Mr. Eastwood until she arrived on the “Changeling” set. But she knew of his reputation for running a tight ship and for finishing even complicated scenes in just a couple of takes.

“I can sometimes roll without even saying a word,” Mr. Eastwood said of his filming process. “I’ll just motion to the cameraman, and he turns it on, and there we go. But she understood what things are like, and she was ready.”

Ms. Jolie described it in other terms. “It made me terribly nervous,” she said. “The first day it moved so quickly. There are big, emotional, heavy things in that movie where it was, maximum, two takes. So I woke up in the morning not feeling relaxed. I would make sure I understood where my character was coming from, I was prepared emotionally, my lines were crisp. I was more ready than I’d ever been on a film because that’s what he demands.” By the end, Ms Jolie — who learned she was pregnant just before she was to shoot her harrowing scenes set in a mental institution — said she felt “this is how I should always work: I should always be this professional and prepared.”

Since winning her Oscar almost 10 years ago Ms. Jolie has carved out a distinctive identity; unlike most other actresses of her age she is interchangeable with no one. Growing up, she said, she found her on-screen role models weren’t actresses but rather “Al Pacino in ‘Dog Day Afternoon,’ Brando in ‘Streetcar,’ Nicholson — I just always liked the men.” That may be part of the reason she has become virtually the only current A-list actress to achieve her status while completely bypassing romantic comedies. Nobody is ever likely to call her “America’s Sweetheart.”

A dark period, when Ms. Jolie was cast as the man eater who broke up Mr. Pitt’s marriage to Jennifer Aniston during the production of the 2005 caper “Mr. and Mrs. Smith,” is behind her. And although in her 20s she was prone to provocative statements about blood, tattoos and bisexuality, in her early 30s she has learned how to feed the beast while making it serve her purposes. Recently she and Mr. Pitt auctioned off pictures of themselves with their newborn twins to People and Hello! magazines, raising an astonishing $14 million for their charity, the Jolie-Pitt Foundation.

Today her career strategy seems more akin to, say, George Clooney’s than to Cameron Diaz’s. She has amassed an impressive record in action-driven hits like the “Tomb Raider” movies and “Gone in 60 Seconds” while making regular (and generally less successful) forays into more serious work, most recently in ensemble pieces like the 2006 drama “The Good Shepherd” or lower-budgeted movies like “A Mighty Heart,” in which several critics suggested that her fine performance was undermined by the fact of her celebrity.

“Changeling,” a big-studio drama that she must carry on her shoulders while submerging the tensile, sexually charged physicality with which she has often defined herself, is another step outside of her comfort zone. And while Ms. Jolie discussed the film with enthusiasm, it was evident that her mind isn’t mainly on movies now. She has taken all of 2008 off from filmmaking and has only one movie lined up — the spy thriller “Edwin A. Salt,” which will begin production in February and which, in an indication of her box office clout in action films, was reconceived for her after Tom Cruise dropped out.In addition she will reprise her vocal performance as Tigress in the sequel to this summer’s “Kung Fu Panda” — the only one of her roughly three dozen movies that any of her children have seen. “It’s a big hit in the house,” she said. “Jack Black is like De Niro to the kids.”

After that, she said, she’ll stay home for another full year, and she expects acting to play a diminishing role in her life as time goes by. For the past several months, since the twins were born, the older kids have been home-schooled, “and they’ve had Mommy and Daddy every day for every meal, and they’ve been very close to us.” It’s not a routine she’s eager to disrupt. Deciding to take a job is “really hard,” she said. “Who’s in school at that time? How can I be sure I don’t do too many long hours? Can the three youngest be on the set every day?”

“As long as I can still be with my family, it’s fun,” she added. “But I only want to do that, and I’m not looking for anything else.”About that family, she and Mr. Pitt aren’t planning to stop at six. “Oh, no,” she said happily. “I mean, I know we seem crazy, just bringing them in one after the other, but we do plan. We make sure one is absorbed completely into the family before we add another. There are moments when we look at everyone around the dinner table, and it’s just crazy, but our family is the greatest thing we’ve done in our lives.”

It’s hardly surprising that the children are Ms. Jolie’s focus right now. (“Just come tell me if you need me to pump,” she said to an assistant before starting the interview.) She worries about the day that Maddox, who is now old enough to use the Internet, will “look up my name and see some kind of sexy pictures or read a story about himself that isn’t true. There’s a lot we’re going to have to explain to them about how public their family is.”

Nonetheless, she said, she looks forward to the day when she can put “Mr. and Mrs. Smith” in the DVD player for the children; “not a lot of people get to see a movie where their parents fell in love.”

“What’s going to be funny is when they think Mom and Dad are a little bit cool,” she added. “Because right now, we’re not cool Mom and Dad.”

“Even video games, you know, it’s: ‘Mom, you can’t play this. You won’t know how.’ Oh, they all think I can’t do anything, that I’m just there to snuggle with. But the other day Madd said, ‘Can you do a cartwheel?’ And I said, ‘Yeah, I can.’ And he was like, ‘Wow, Mom.’ And I thought: ‘Oh, yeah. I can do some things. You wait. You’ll find out. I’m capable.’ ”</FONT>